ideas on how to build a multi-unit apartment building on a half acre of land. Anyone have a great blueprint or website? I’d like to try and get at least 10 units on it.
Yeah, build em real high. 
Check you local laws regarding the need for an architect.
In Ohio, you need an architect if you want to build anything bigger than a single family residence.
Also be sure to check the zoning restrictions before you purchase. It’s important to know that some zoning can be changed, but only so far. It’s kinda hard to put a nuclear plant in the middle of an upper-middle class residential neighborhood. The HOA would have a field day!
you need to carefully investigate zoning and talking with the planning comission folks. there are all kinds of restrictions and consdieration (like parking). A 1/2 acre lot if pretty small unless you are building in the middle of a large urbanized city.